While it is known to provide grease guns which make use of auxiliary pumps or external pneumatic pressure sources to vary the volume and pressure of grease supplied, such devices require the use of expensive motors or sources of external power. Accordingly, they are not usually portable.
It is also known to provide a variable stage grease gun which utilizes a user operated switch or coupling to vary the grease gun from one application to another. Such an arrangement requires the user to appropriately engage and disengage the gun in the appropriate conditions but the user may be unaware of when desired changes to the gun operation are needed. Accordingly, there remains room for improvement and variation within the art with respect to grease guns.